Effect of Fatigue Damage Parameter on the Cumulative Life of a Turbine Rotor Under Multiaxial Loading

Abstract

The effect of the fatigue damage parameter on the cumulative life of a high-speed turbine rotor has been estimated through finite element approach. Two most commonly used multiaxial fatigue damage models based on critical plane approach-Fatemi Socie (FS) model, and Kandil Brown and Miller model (KBM) have been used to estimate the fatigue life. Structural integrity test was carried out in spin test facility to validate the simulation results. KBM model for fatigue life estimation and LMP model for creep damage predicted a cumulative life within a factor of 1.5 scatter band of the experimental value. The combination of FS model for fatigue life estimation and LMP model could predict cumulative life only within a scatter band of 2. Some of the shortcomings attributed to LDS method can be obviated using a suitable fatigue damage parameter. The study provides invaluable input and confidence for the life prediction of high-speed gas turbine rotors.